1984 Supra 351w - No start after running for a while

[chris young]

"the Holley 4bbl has a float level that you must adjust so that the boosters will not leak into intake , i switched to a edlebrock and it starts up instantly

Yes it does, the problem is you want as much gas in the bowl as possible without going so high that it starts leaking out the boosters. To my knowledge, no one has posted a float level based on the tilt of the carb, so you have to adjust by trial and error. Since you have to keep removing the bowl to do so, it gets pretty tedious. I'm not so sure that you need to buy a new carb to solve the problem though. In my case, I decided that the carb was designed to run level, so I leveled it, new studs and a wedge spacer (I stacked 2 X 5 deg but you can get 1X10 deg, it was just the easiest way to proceed through my local auto parts shop) There are loads of these boats running around without wedge spacers in them so it's completely doable with just float level I'm sure. I think what ends up happening quite often, is someone decides to refresh the carb, and when they set the float levels they use the Holley recommended float settings, and the problem begins.

[lively]

"the Holley 4bbl has a float level that you must adjust so that the boosters will not leak into intake , i switched to a edlebrock and it starts up instantly

Yes it does, the problem is you want as much gas in the bowl as possible without going so high that it starts leaking out the boosters. To my knowledge, no one has posted a float level based on the tilt of the carb, so you have to adjust by trial and error. Since you have to keep removing the bowl to do so, it gets pretty tedious. I'm not so sure that you need to buy a new carb to solve the problem though. In my case, I decided that the carb was designed to run level, so I leveled it, new studs and a wedge spacer (I stacked 2 X 5 deg but you can get 1X10 deg, it was just the easiest way to proceed through my local auto parts shop) There are loads of these boats running around without wedge spacers in them so it's completely doable with just float level I'm sure. I think what ends up happening quite often, is someone decides to refresh the carb, and when they set the float levels they use the Holley recommended float settings, and the problem begins.

problem with me is the holley was fun and i know it was standard on the supras , i was just never knowledgeable enough to get it quite right , lol i still have it in the shed but the edlebrock marine i put on has had no problems . main issue was i had alot of backfire in the holley with my ign timing and the diaphragm inside the metering block had to change that out a few times lol

[UKandH]

Supras are fitted (as we all know) with 4160 marine Hollies, but there is an option, the 4150, this has 2 metering blocks instead of one and fully adjustable floats that can be adjusted without taking the bowls off. All you do is crack the cover off of the adjuster, turn the screw until fuel trickles out of the hole and refit the plug. Do front and rear bowls in the same fashion when on the water and the carb has perfect set up for marine use where the engine is mounted at an angle. The 4160 cant cope very well with this where as the 4150 can.

Saying that im still running a 4160 thats sweet as a nut after its overhaul a few months ago..

[hockeyGTP]

So I finally got the take the boat back out and try a few things. Saturday after sitting for a few hours in the cove it was slow to turn over but started up. Sunday after sitting a few hours it was slow to turn over again. I held the butterfly flap closed and it started turning over faster and started right up.

[lively]

So I finally got the take the boat back out and try a few things. Saturday after sitting for a few hours in the cove it was slow to turn over but started up. Sunday after sitting a few hours it was slow to turn over again. I held the butterfly flap closed and it started turning over faster and started right up.

check you timing , 10 degrees BTDC is a good place i would say 6-10 degrees is the sweet spot .. thats prob your slow turning issue ..

[Salty87]

how old are your battery cables? inefficiencies in the circuit will weaken it.

[Supra_Comp]

Be sure to check the voltage on the positive side of the ignition coil and feel how hot it is. Also check the resistance of the primary coil. What type of dizzy are you running? Generally speaking you will want to see 0.7 Ohms resistance and 9.0 volts while running on the positive side of the coil. If you see anything higher than that, your ballast resistor may be shot or may have wiring issues.

I had this issue on my boat for years and looked right past it assuming that since it ran cold it must be a carb issue.

[hockeyGTP]

Forgive my ignorance, please. I haven't been able to check the boat because after I unhooked the trailer I fractured my ankle. I did notice the last time that where the positive battery wire hooks up at the back of the engine under the gray cover was getting hot and started to smoke some also. I don't know what that part is called, or where the primary coil is, or what a dizzy is. I am hoping to get in the boat Monday and really look at it a lot more.

[Supra_Comp]

No problem man. The part your talking about is probably the starter solenoid, where all the ignition and accessories get the power from.

The ignition coil is the round cylinder that has a single spark plug wire from (usually mounted on the top of the intake manifold by the car or on the front of the engine). That plug wire provides power to the dizzy (aka distributor). On the ignition coil, there is a power wire and another wire on the + terminal that goes to the distributor. If that wire is connected directly to the starter solenoid, it means it is seeing 12 volts and can overheat the coil after running and cause symptoms similar to vapour lock and poor performance/starting. The coil should be hooked up with an inline ballast resistor (white ceramic block which should be under that cover you mentioned) which will reduce the voltage down to 9 volts.

Have a look at this first and take a picture of the wiring hook up.

[Supra_Comp]

Use post 39 for reference.

https://forum.supraboats.com/showthr...k-Issues/page4